Method for producing cosmetic rubber sponge and cosmetic rubber sponge

Abstract

To provide a method for producing cosmetic rubber sponges with antibacterial properties without significantly altering a conventional production process for NBR puffs, and cosmetic rubber sponges.SOLUTION: The method for producing cosmetic rubber sponges, has: a mixing and stirring step of charging a predetermined amount of a raw material including a liquid NBR (nitrile butadiene rubber), a vulcanizing agent, a vulcanizing accelerator, a vulcanizing accelerator aid, an antimicrobial agent, and a foam stabilizer into a mixer, followed by mixing and stirring to produce a stirred product; a molded product production step of charging the stirred product into a mold of a predetermined shape, foaming and molding it to produce a molded product; an aging step of aging the molded product for a predetermined time to produce the aged product; and a vulcanizing step of vulcanizing the aged product to produce a vulcanizate, wherein the vulcanizing agent is sulfur, the vulcanizing accelerator aid is a first predetermined amount of zinc oxide, the antimicrobial agent is a second predetermined amount of zinc oxide which is different from the first predetermined amount of the vulcanizing accelerator aid. The method further includes a removal step of removing sulfur adhering to a surface of the vulcanizate.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for producing a cosmetic rubber sponge and a cosmetic rubber sponge. [Background technology]

[0002] Cosmetic rubber sponges (cosmetic puffs) are used to apply cosmetics such as foundation to the user's face. In particular, cosmetic puffs (hereinafter referred to as "NBR puffs") made primarily of acrylonitrile-butadiene rubber (NBR), a typical latex sponge rubber, are widely used because they are cushioned, glide smoothly on the skin, and are easy to handle. Furthermore, they are hydrophobic and compatible with oily foundations. However, because NBR puffs are hydrophobic, it is difficult to completely remove foundation from an NBR puff with water after a user applies foundation to it. If foundation remains on the surface of an NBR puff and dirt adheres to the foundation, it can cause problems for the user's skin. Therefore, a technology has been proposed to impart antibacterial properties to NBR puffs by adding an antibacterial agent during the manufacturing process (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-131137 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology of Patent Document 1 utilizes the antibacterial properties of plant essential oils, which requires the use of materials that are not used in the manufacturing process of conventional NBR puffs, and also requires the addition of a process that is different from the manufacturing process of conventional NBR puffs.

[0005] In light of the above, the present invention provides a method for producing an antibacterial cosmetic rubber sponge, and a cosmetic rubber sponge, without significantly changing the conventional NBR puff production process. [Means for solving the problem]

[0006] The first invention is a method for manufacturing a cosmetic rubber sponge, comprising: a mixing and stirring process in which materials and chemicals including liquid NBR (nitrile butadiene rubber), a vulcanizing agent, a vulcanization accelerator, a vulcanization acceleration aid, an antibacterial agent, and a foam stabilizer are charged into a stirrer, and then mixed and stirred to produce a mixed product; a molded product production process in which the mixed product is charged into a mold of a predetermined shape, and foamed and molded to produce a molded product; an aging process in which the molded product is aged for a predetermined period of time to produce a matured product; and a vulcanization process in which the matured product is vulcanized to produce a vulcanized product, wherein the vulcanizing agent is sulfur, and the antibacterial agent is antibacterial zinc oxide, which exhibits antibacterial properties after the cosmetic rubber sponge is produced, and the amount of the antibacterial agent contained in the mixed product is a numerical value of 0.1 phr (per hundred ruble) or more and 3.0 phr or less, and further comprising a removal process in which the sulfur adhering to the surface of the vulcanized product is removed.

[0007] Generally, vulcanization using sulfur is performed in the manufacturing process of NBR puffs. Because sulfur has antibacterial properties, if sulfur remains on the surface of the NBR puff (the portion exposed to the outside), it will exhibit a corresponding antibacterial effect. However, if sulfur remains on the surface of the NBR puff, it generates a sulfurous odor and, depending on the nature and condition of the user's skin and the amount of remaining sulfur, may have an adverse effect on the user's skin. Therefore, in the configuration of the first invention, sulfur adhering to the surface of the vulcanized product is removed in a removal process. Then, zinc oxide is added as an antibacterial agent to exert antibacterial effects after the NBR puff is manufactured. Incidentally, zinc oxide is known to function as, for example, a vulcanizing agent, a vulcanization accelerator, or a coagulant in the manufacturing process of NBR puffs. In this specification, zinc oxide that functions in the manufacturing process is referred to as "zinc oxide for processing." Because zinc oxide is known as zinc oxide for processing, it was expected that even if a small amount of zinc oxide was added as an antibacterial agent, it would function as zinc oxide for processing and would not exhibit antibacterial effects after the NBR puff is manufactured. However, the inventors of the present invention found that when a small amount of zinc oxide (antibacterial zinc oxide) was added in the manufacturing process of NBR puffs, the manufactured NBR puffs actually exhibited antibacterial properties, contrary to the above-mentioned expectation. According to the configuration of the first invention, by simply adding zinc oxide, which has been conventionally used in the manufacturing process, it is possible to manufacture antibacterial cosmetic rubber sponges without making major changes to the conventional manufacturing process of NBR puffs.

[0008] The second invention is a method for producing a cosmetic rubber sponge, in which, in the configuration of the first invention, process zinc oxide is used in the mixing and stirring process as zinc oxide to function in the manufacturing process of the cosmetic rubber sponge, the antibacterial zinc oxide is contained in the stirred mixture separately from the process zinc oxide, and the amount of the antibacterial zinc oxide is less than the amount of the process zinc oxide.

[0009] A third invention is a method for producing a cosmetic rubber sponge according to the second invention, wherein the particle size of the antibacterial zinc oxide is larger than the particle size of the process zinc oxide.

[0010] According to the third aspect of the present invention, the particle size of the zinc oxide for processing is smaller than that of the zinc oxide for antibacterial purposes, and therefore the zinc oxide for processing has a relatively large specific surface area. Therefore, the zinc oxide for processing reacts easily with other substances, and therefore functions easily as, for example, a vulcanization accelerator. On the other hand, the zinc oxide for antibacterial purposes does not react easily with other substances, and therefore does not function in the manufacturing process of the NBR puff, but remains after the NBR puff is manufactured to exert its antibacterial effect.

[0011] The fourth invention is a method for producing a cosmetic rubber sponge, in which, in the configuration of any one of the first to third inventions, the antibacterial zinc oxide is composed of zinc oxide having a plurality of particle sizes (d50).

[0012] According to the fourth aspect of the present invention, the particle size distribution is wider than when the antibacterial zinc oxide is composed of zinc oxide with a single particle size, making it possible to produce a cosmetic rubber sponge that exhibits an even antibacterial effect at all positions.

[0013] The fifth invention is a cosmetic rubber sponge that is primarily made of NBR (nitrile butadiene rubber) and is manufactured using sulfur in the vulcanization process, and that contains antibacterial zinc oxide to exert antibacterial properties after the production of the cosmetic rubber sponge, in addition to process zinc oxide necessary for the cosmetic rubber sponge to function in the manufacturing process, and that no sulfur is present on the surface of the cosmetic puff that is exposed to the outside.

[0014] A sixth invention is a cosmetic rubber sponge according to the fifth invention, wherein the particle size of the antibacterial zinc oxide is larger than the particle size of the process zinc oxide.

[0015] A seventh invention is a cosmetic rubber sponge having the configuration of the fifth or sixth invention, wherein the antibacterial zinc oxide is composed of zinc oxide having a plurality of particle sizes (d50). [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a method for producing an antibacterial cosmetic rubber sponge and a cosmetic rubber sponge, without making major changes to the conventional NBR puff production process. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic view showing a cosmetic rubber sponge according to an embodiment of the present invention. [Figure 2] 1 is a schematic flowchart showing a method for manufacturing a cosmetic rubber sponge. [Figure 3] FIG. 10 is a diagram showing test results. [Figure 4] FIG. 10 is a diagram showing test results. [Figure 5] FIG. 10 is a diagram showing test results. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Note that the description will be limited to the basic configuration of the present invention, and will omit explanations of configurations that can be implemented by those skilled in the art.

[0019] Fig. 1 is a schematic diagram showing a cosmetic rubber sponge 1 (hereinafter referred to as "sponge 1") according to one embodiment of the present invention. Sponge 1 is mainly composed of NBR (nitrile butadiene rubber). NBR is a copolymer of acrylonitrile and butadiene produced by emulsion polymerization.

[0020] The NBR content is defined as a value between 90% by weight and 98% by weight based on the total weight of the composition of sponge 1. The content or amount of raw materials, such as materials and chemicals, used to manufacture sponge 1 is expressed as "phr (per hundred rubeers)," which means parts by weight per 100 parts by weight of NBR.

[0021] A vulcanizing agent, a vulcanization accelerator, a vulcanization accelerator assistant, a foaming agent, a bubble stabilizer, a coagulant, a dispersant, etc. are added to manufacture the sponge 1. Furthermore, in this embodiment, after manufacturing the sponge 1, zinc oxide (ZnO) particles are added in the manufacturing process to impart antibacterial properties.

[0022] Sulfur is used as a vulcanizing agent. The content of the vulcanizing agent is between 0.5 phr and 3.0 phr. The sulfur causes a reaction that chemically bonds the polymer chains of NBR, making them three-dimensional. By crosslinking, the rubber elastic properties become more pronounced.

[0023] Examples of vulcanization accelerators that can be used include thiazole-based vulcanization accelerators such as MZ (zinc salt of 2-mercaptobenzothiazole), dithiocarbamic acid-based vulcanization accelerators such as EZ (zinc diethyldithiocarbamate) and BZ (zinc dibutyldithiocarbamate), thiourea-based vulcanization accelerators such as EUR (N,N'-diethylthiourea), guanidine-based vulcanization accelerators, xanthogenic acid-based vulcanization accelerators, and thiuram-based vulcanization accelerators, which can be used alone or in combination. The vulcanization accelerator concentration is between 0.5 phr and 4.0 phr.

[0024] Zinc oxide (ZnO) is used as a vulcanization accelerator aid. The content of zinc oxide as a vulcanization accelerator aid (hereinafter referred to as "zinc oxide for processing") is a value between 3 phr (per hundred rubber) and 5 phr, both inclusive, relative to NBR. This value is an example of a first predetermined amount. The zinc oxide powder for processing is zinc oxide powder having a particle diameter (d50) of between 10 nanometers (nm) and 80 nanometers (nm), both inclusive. In this embodiment, the particle diameter (d50) of the powder is 35 nanometers (nm). The particle size distribution of the powder is normal. Note that, unlike this embodiment, for example, any grade of the composite activated zinc oxide META-Z L series manufactured by Inoue Lime Industry Co., Ltd. may be used as the vulcanization accelerator aid.

[0025] In addition to the zinc oxide for processing described above, zinc oxide (hereinafter referred to as "antibacterial zinc oxide") is added to the sponge 1 after its production is completed in order to exert its antibacterial effect. The content of the antibacterial zinc oxide is a value between 0.10 phr and 3.0 phr. Preferably, the content of the antibacterial zinc oxide is a value between 0.15 phr and 2.50 phr. More preferably, the content of the antibacterial zinc oxide is a value between 0.20 phr and 2.00 phr. Note that, unlike the present embodiment, when zinc oxide is used to function as a vulcanizing agent or a gelling aid in the production process, antibacterial zinc oxide is added in addition to the zinc oxide used in the production process. Whether or not zinc oxide for processing is used, the gist of the present invention is to add a small amount of antibacterial zinc oxide to exert its antibacterial effect after production. Contrary to the expectation that the trace amount of antibacterial zinc oxide would function as zinc oxide for processing and be consumed, the antibacterial effect was actually exhibited even after the NBR puff was produced, which is the effect of the present invention and the basis for its novelty and inventive step.

[0026] The antibacterial zinc oxide powder has a particle diameter (d50) of 20 nanometers (nm) or more and 120 nanometers (nm) or less, but is larger than the particle diameter of zinc oxide for processing. In this embodiment, the particle diameter (d50) of the antibacterial zinc oxide powder is 100 nanometers (nm). The particle size distribution of the powder is normal.

[0027] As described above, both the zinc oxide for processing and the antibacterial zinc oxide are ultrafine particles. However, the particle diameter of the antibacterial zinc oxide is larger than that of the zinc oxide for processing. Unlike this embodiment, the particle diameters of the zinc oxide for processing and the antibacterial zinc oxide may be the same. Even in this case, only the amount of zinc oxide for processing is added that is necessary for the production of the sponge 1. Therefore, any excess zinc oxide for antibacterial use is not used in the production process of the sponge 1, and the antibacterial zinc oxide exerts its antibacterial effect after the production of the sponge 1. Unlike this embodiment, the antibacterial zinc oxide may be a mixture of powders with multiple particle sizes, rather than a single particle size (d50). For example, a combination of zinc oxides with particle sizes of 25 nm, 35 nm, and 100 nm may be used as the antibacterial zinc oxide. For example, zinc oxide having particle sizes of 25 nm and 35 nm may be used at 50% each, zinc oxide having particle sizes of 35 nm and 100 nm at 50% each, zinc oxide having particle sizes of 25 nm and 100 nm at 50% each, or zinc oxide having particle sizes of 25 nm, 35 nm, and 100 nm may be used at one-third each. Note that when powders having different particle sizes are mixed, the ratio of each particle size is not limited to the above.

[0028] The foaming agent may be, for example, an anionic surfactant or a nonionic surfactant. Specifically, potassium or sodium salts of ricinoleic acid, oleic acid, lauric acid, or castor oil fatty acid are used. The amount of foaming agent used is between 0.5 phr and 5.0 phr.

[0029] As a foam stabilizer, Trimene base (Ethane, chloro-, polymer with ammonia and formaldehyde) or CoreTex TNM-14S (Polyalkylene Glycol Derevatives) is used. The amount of foam stabilizer used is between 0.1 phr and 5.0 phr in terms of solid content.

[0030] The coagulant (gelling agent) used is sodium silicofluoride or bentonite, etc. The amount of coagulant used is between 0.5 phr and 5.0 phr by weight.

[0031] Dispersants such as sodium butylnaphthalene sulfonate are used. The dispersant content is between 0.2 phr and 1.0 phr.

[0032] In addition to the above materials or agents, compounding agents such as ultraviolet absorbers, softeners, fillers, coloring materials, and antifungal agents may be used as appropriate.

[0033] Next, a method for manufacturing the sponge 1 will be described with reference to the accompanying drawings.

[0034] FIG. 2 is a flowchart showing a method for manufacturing the sponge 1.

[0035] First, liquid NBR, vulcanizing agent, vulcanization accelerator, vulcanization accelerator aid, antibacterial zinc oxide, foam stabilizer, dispersant, etc. are placed in a mixer and mixed and stirred at a speed of 30 to 100 rpm (Step ST1). In Step ST1, viscosity modifier and pH adjuster are further added as needed to prevent problems with the stability of the liquid NBR particles and the occurrence of defective products that may occur during the manufacturing process. The state of the raw materials at the completion of Step ST1 is called the "mixed product."

[0036] Next, the coagulant and the mixture are placed in a mold of a predetermined shape, and foamed and molded using a foaming machine (step ST2). The state of the raw material at the completion of step ST2 is called a "molded product."

[0037] Next, the molded product is aged in the foaming mold (step ST3). The aging temperature and time are between 25 and 35 degrees Celsius, and between 1 and 3 hours. The state of the raw material at the completion of step ST3 is called the "aged product."

[0038] Next, the aged material is vulcanized in a vulcanizer (step ST4). The vulcanizer is a device that vaporizes the vulcanizing agent into a gas and transforms the aged material into an elastic substance. The aged material is vulcanized in the vulcanizer at a temperature between 85 and 105 degrees Celsius for a period between 40 and 65 minutes. The state of the raw materials at the completion of step ST4 is called the "vulcanized material."

[0039] Next, the vulcanized product is removed from the mold, and sulfur adhering to the surface of the vulcanized product is removed (step ST5).In step ST5, the vulcanized product is washed with a neutral washing liquid.

[0040] The components of the neutral cleaning solution are, for example, at least one selected from surfactants such as polyoxyalkylene alkyl ethers, mixtures of hydroxyalkanesulfonates and alkene sulfonates, polyoxyalkylene alkyl ether sulfates, fatty acid salts, polyoxyethylene alkyl ethers, alkylhydroxysulfobetaines, sodium polyoxyalkylene alkyl ether sulfates, sodium dialkyl sulfosuccinates, alkyl glyceryl ethers, alkyl glycosides, alkyltrimethylammonium salts, alkyl glyceryl ethers, etc. Furthermore, water, stabilizers, and dispersants may be added to the neutral cleaning solution as appropriate.

[0041] In step ST5, sulfur present on the surface of the vulcanized product is removed. For example, washing is performed using a neutral washing solution at a temperature between 50 and 90 degrees Celsius for a period of between about 10 and 100 minutes. A washing machine such as a drum washing machine can be used for washing. This washing process is performed multiple times (for example, 5 to 15 times) to completely remove sulfur present on the surface of the vulcanized product. Note that washing by soaking is also possible, but in this case, it is preferable to stir the solution from time to time to ensure that it is evenly distributed.

[0042] Finally, the washed vulcanized product is cut into a desired size (step ST6).

[0043] The cleaning step (ST5) may be carried out after the cutting step (ST6).

[0044] Because zinc oxide also functions as a vulcanizing agent, vulcanization accelerator, and coagulant, it was expected that the small amount of antibacterial zinc oxide contained in the mixture would function and be consumed during the NBR puff manufacturing process. However, contrary to expectations, the antibacterial effect was demonstrated in the manufactured NBR puffs.

[0045] Second Embodiment Next, the second embodiment will be described with respect to the differences from the first embodiment.

[0046] In the second embodiment, a substance other than zinc oxide (ZnO) is used as the vulcanization accelerator aid, such as a fatty acid such as stearic acid, oleic acid, or lauric acid, or a metal salt thereof, or a metal oxide or hydroxide such as zinc carbonate, magnesium oxide, or calcium hydroxide.

[0047] The amount of the vulcanization accelerator used is, for example, 0.1 phr or more and 3.0 phr or less in the case of stearic acid, and 0.5 phr or more and 10 phr or less in the case of magnesium oxide.

[0048] In the second embodiment, antibacterial zinc oxide is used, as in the first embodiment. In the second embodiment, zinc oxide also functions as a vulcanizing agent, a vulcanization accelerator, or a coagulant, so it was expected that the trace amount of antibacterial zinc oxide contained in the stirred material would be consumed in the manufacturing process of the NBR puff. However, contrary to this expectation, the antibacterial effect was exhibited in the manufactured NBR puff.

[0049] <Antibacterial test results of the examples> 3 to 5 show the results of the antibacterial test on Sponge 1.

[0050] FIG. 3 shows the results of an antibacterial test on a sponge (hereinafter referred to as an "unwashed sponge") manufactured without carrying out the washing step (step ST5) in the manufacturing process of the second embodiment described above. For comparison, an antibacterial test was also conducted on cotton. Note that the unwashed sponge was also subjected to a general washing step. The general washing step is intended to remove fine particles from the sponge, and is not intended to remove all of the sulfur remaining on the sponge surface. Therefore, sulfur remains on the sponge surface, and the antibacterial effect of sulfur also remains.

[0051] Figure 3 shows the results of an antibacterial test (JIS L 1902) using the bacterial liquid absorption method for unwashed sponges. Specifically, the following test steps were carried out. The bacterial liquid concentration was 100 million CFU / mL. 1. Place the test sample (0.4g) into a vial. 2. Allow the sample to absorb the bacterial solution (0.2 mL). 3. Incubate at 37°C for 24 hours 4. Add 20 mL of washout solution to wash out the test bacteria from the test sample, and measure the number of viable bacteria in the washout solution using the pour plate culture method or luminescence measurement method. 5. Antibacterial activity value = {log (target sample, number of viable bacteria after incubation) - log (target sample, number of viable bacteria immediately after inoculation)} - {log (test sample, number of viable bacteria after incubation) - log (test sample, number of viable bacteria immediately after inoculation)}

[0052] As shown in Figure 3, many bacteria (E. coli) are visible on the comparative cotton. In contrast, no bacteria are visible on the unwashed sponge, regardless of the amount of antibacterial zinc oxide contained. This is thought to be due to the antibacterial effect of the sulfur remaining on the sponge surface.

[0053] Figure 4 shows the results of the same antibacterial test on the unwashed sponge as described above, but for the sponge 1 of the second embodiment (i.e., a sponge manufactured by carrying out a washing process). However, the leftmost photograph is a comparison, showing a sponge manufactured without adding any antibacterial zinc oxide (0 phr) during the manufacturing process. A large number of bacteria (E. coli) are visible in the comparison. This indicates that the sulfur remaining on the sponge surface was removed by washing in the washing process (step ST5).

[0054] When antibacterial zinc oxide was added according to the embodiment of the present invention (0.5 phr, 1.0 phr, 2.0 phr), it was visually observed that the number of bacteria was clearly reduced compared to the control (0 phr). In fact, even in the case of 0.5 phr, the number of bacteria was reduced by more than three orders of magnitude compared to the control. Furthermore, a separate antibacterial test confirmed that antibacterial zinc oxide exerted its antibacterial effect even when the content was 0.1 phr.

[0055] FIG. 5 shows the results of a test performed on the sponge 1 of this embodiment using a different test method from the above-mentioned test method. Specifically, a halo test was performed according to JIS L 1902. The bacterial solution used was the same as that shown in FIGS. 3 and 4. In the halo test, the bacterial solution is placed in a petri dish, and a sample piece is placed on top of it to observe the behavior of the bacterial solution. FIG. 5 is a photograph taken from the bottom of the petri dish, and the white rectangular object in the center is the sample piece. From FIG. 5, when no antibacterial zinc oxide was added (0 phr) and when the antibacterial zinc oxide content was 0.5 phr, bacteria were visually present even below the sample piece. This also indicates that the sulfur remaining on the sponge surface was removed by washing in the washing process (step ST5). When the antibacterial zinc oxide content was 1.0 phr and 2.0 phr, no bacteria were present below the sample piece; rather, a halo-shaped zone was observed around the sample piece. This indicates that the antibacterial zinc oxide exerts its antibacterial effect.

[0056] The cosmetic rubber sponge and the cosmetic rubber sponge of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the present invention. Furthermore, the above-described embodiments can be combined as appropriate, provided that no technical contradiction arises. [Explanation of symbols]

[0057] 1 cosmetic rubber sponge

Claims

1. A method for manufacturing a cosmetic rubber sponge, comprising: a mixing and stirring process in which raw materials and chemicals including liquid NBR (nitrile butadiene rubber), a vulcanizing agent, a vulcanization accelerator, a vulcanization accelerator assistant, an antibacterial agent, and a foam stabilizer are introduced into a stirrer, and then mixed and stirred to produce a mixture; a molded product manufacturing step of introducing the agitated mixture into a mold having a predetermined shape, and foaming and molding the mixture to manufacture a molded product; an aging step of aging the molded product for a predetermined time to produce a aged product; a vulcanization step of vulcanizing the aged product to produce a vulcanized product; and the vulcanizing agent is sulfur; The antibacterial agent is antibacterial zinc oxide, which serves as zinc oxide for exerting antibacterial activity after the production of the cosmetic rubber sponge, the amount of the antibacterial agent contained in the stirred mixture is equal to or greater than 0.1 phr (per hundred rubber) and equal to or less than 3.0 phr, moreover, The method for producing a cosmetic rubber sponge includes a removing step of removing the sulfur adhering to the surface of the vulcanizate.

2. zinc oxide for processing is used as zinc oxide for functioning in the manufacturing process of the cosmetic rubber sponge, 2. The method for producing a decorative rubber sponge according to claim 1, wherein the antibacterial zinc oxide is contained in the agitated mixture separately from the process zinc oxide.

3. The method for producing a cosmetic rubber sponge according to claim 2, wherein the particle size of the antibacterial zinc oxide is larger than the particle size of the process zinc oxide.

4. The method for manufacturing a cosmetic rubber sponge according to any one of claims 1 to 3, wherein the antibacterial zinc oxide is composed of zinc oxide having a plurality of particle sizes (d50).

5. A cosmetic rubber sponge made mainly from NBR (nitrile butadiene rubber) and using sulfur in the vulcanization process. In addition to the process zinc oxide necessary for functioning in the manufacturing process of the cosmetic rubber sponge, the cosmetic rubber sponge contains antibacterial zinc oxide for exerting antibacterial activity after the manufacturing of the cosmetic rubber sponge, The sulfur is not present on the surface of the cosmetic puff that is exposed to the outside. Cosmetic rubber sponge.

6. 6. The cosmetic rubber sponge according to claim 5, wherein the particle size of the antibacterial zinc oxide is larger than the particle size of the process zinc oxide.

7. The cosmetic rubber sponge according to claim 5 or 6, wherein the antibacterial zinc oxide is composed of zinc oxide having a plurality of particle sizes (d50).

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